In assisted steering systems of this kind which are presently available, the electric motor exerts its assistance action on the steering column by causing it to pivot. But experience shows that the response of the motor to the force exerted by the steering column on the rack is relatively slow and that these assisted steering systems have poor endurance.
U.S. Pat. No. 4,415,054 describes a motor vehicle steering system of the above type, in which the electric motor is connected directly to the rack on which it may act by moving it longitudinally.